Diamond-like carbon film

ABSTRACT

Apparatuses and methods to manufacture integrated circuits are described. A method of forming film on a substrate is described. The film is formed on a substrate by exposing a substrate to a diamond-like carbon precursor having an sp 3  content of greater than 40 percent. Methods of etching a substrate are described. Electronic devices comprising a diamond-like carbon film are also described.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. application Ser.No. 16/002,222, filed on Jun. 7, 2018, which claims priority to U.S.Provisional Application No. 62/516,828, filed Jun. 8, 2017 and claimspriority to U.S. Provisional Application No. 62/546,266, filed Aug. 16,2017, the entire disclosures of which are hereby incorporated byreference.

TECHNICAL FIELD

Embodiments of the present disclosure pertain to the field of electronicdevice manufacturing, and in particular, to an integrated circuit (IC)manufacturing. More particularly, embodiments of the disclosure providemethods of depositing diamond-like carbon hard mask films, which can beused for patterning applications.

BACKGROUND

Integrated circuits have evolved into complex devices that can includemillions of transistors, capacitors, and resistors on a single chip. Theevolution of chip designs continually requires faster circuitry andgreater circuit density. The demands for faster circuits with greatercircuit densities impose corresponding demands on the materials used tofabricate such integrated circuits. In particular, as the dimensions ofintegrated circuit components are reduced, it is necessary to use lowresistivity conductive materials as well as low dielectric constantinsulating materials to obtain suitable electrical performance from suchcomponents.

The demands for greater integrated circuit densities also impose demandson the process sequences used in the manufacture of integrated circuitcomponents. For example, in process sequences that use conventionalphotolithographic techniques, a layer of energy sensitive resist isformed over a stack of material layers disposed on a substrate. Theenergy sensitive resist layer is exposed to an image of a pattern toform a photoresist mask. Thereafter, the mask pattern is transferred toone or more of the material layers of the stack using an etch process.The chemical etchant used in the etch process is selected to have agreater etch selectivity for the material layers of the stack than forthe mask of energy sensitive resist. That is, the chemical etchantetches the one or more layers of the material stack at a rate muchfaster than the energy sensitive resist. The etch selectivity to the oneor more material layers of the stack over the resist prevents the energysensitive resist from being consumed prior to completion of the patterntransfer.

As the pattern dimensions are reduced, the thickness of the energysensitive resist must correspondingly be reduced in order to controlpattern resolution. Such thin resist layers can be insufficient to maskunderlying material layers during the pattern transfer step due toattack by the chemical etchant. An intermediate layer (e.g., siliconoxynitride, silicon carbine, or a carbon film), called a hard mask, isoften used between the energy sensitive resist layer and the underlyingmaterial layers to facilitate pattern transfer because of greaterresistance to the chemical etchant. As critical dimensions (CD)decrease, hard mask materials having the desired etch selectivityrelative to underlying materials (e.g., oxides and nitrides) as well ashigh deposition rates are desired.

SUMMARY

Apparatuses and methods to manufacture integrated circuits aredescribed. In one or more embodiments, a method of forming film on asubstrate is described. In one embodiment, a film is formed on asubstrate by exposing a substrate to a diamond-like carbon precursorhaving an sp³ content greater than 40 percent.

In one or more embodiments, a method of etching a substrate isdescribed. In one embodiment, a carbon hard mask is formed on asubstrate. The carbon hard mask has at least one opening and is formedby exposing the substrate to a diamond-like carbon precursor having astructure of formula (I) or a structure of formula (II)

wherein each of R₁-R₂₀ are independently selected from H, a halogen or asubstituted or unsubstituted C₁-C₄ alkyl. The substrate is then etchedthrough the at least one opening.

In one or more embodiments, an electronic device is described. Theelectronic device comprises a film on a substrate. The film comprises adiamond-like carbon material having an sp³ content greater than 40percent.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this disclosure and are therefore not to beconsidered limiting of its scope, for the disclosure may admit to otherequally effective embodiments. The embodiments as described herein areillustrated by way of example and not limitation in the figures of theaccompanying drawings in which like references indicate similarelements.

FIG. 1A illustrates a cross-sectional view of a substrate according tothe prior art;

FIG. 1B illustrates a cross-sectional view of a substrate according tothe prior art;

FIG. 1C illustrates a cross-sectional view of a substrate according tothe prior art;

FIG. 1D illustrates a cross-sectional view of a substrate according tothe prior art;

FIG. 1E illustrates a cross-sectional view of a substrate according tothe prior art;

FIG. 2A illustrates a cross-sectional view of a substrate according toone or more embodiment;

FIG. 2B illustrates a cross-sectional view of a substrate according toone or more embodiment;

FIG. 2C illustrates a cross-sectional view of a substrate according toone or more embodiment;

FIG. 2D illustrates a cross-sectional view of a substrate according toone or more embodiment;

FIG. 2E illustrates a cross-sectional view of a substrate according toone or more embodiment;

FIG. 3A illustrates a cross-sectional view of a substrate according toone or more embodiment;

FIG. 3B illustrates a cross-sectional view of a substrate according toone or more embodiment; and

FIG. 3C illustrates a cross-sectional view of a substrate according toone or more embodiment.

DETAILED DESCRIPTION

Before describing several exemplary embodiments of the disclosure, it isto be understood that the disclosure is not limited to the details ofconstruction or process steps set forth in the following description.The disclosure is capable of other embodiments and of being practiced orbeing carried out in various ways.

A “substrate” as used herein, refers to any substrate or materialsurface formed on a substrate upon which film processing is performedduring a fabrication process. For example, a substrate surface on whichprocessing can be performed include materials such as silicon, siliconoxide, strained silicon, silicon on insulator (SOI), carbon dopedsilicon oxides, amorphous silicon, doped silicon, germanium, galliumarsenide, glass, sapphire, and any other materials such as metals, metalnitrides, metal alloys, and other conductive materials, depending on theapplication. Substrates include, without limitation, semiconductorwafers. Substrates may be exposed to a pretreatment process to polish,etch, reduce, oxidize, hydroxylate, anneal and/or bake the substratesurface. In addition to film processing directly on the surface of thesubstrate itself, in the present disclosure, any of the film processingsteps disclosed may also be performed on an under-layer formed on thesubstrate as disclosed in more detail below, and the term “substratesurface” is intended to include such under-layer as the contextindicates. Thus for example, where a film/layer or partial film/layerhas been deposited onto a substrate surface, the exposed surface of thenewly deposited film/layer becomes the substrate surface.

As used in this specification and the appended claims, the terms“precursor”, “reactant”, “reactive gas” and the like are usedinterchangeably to refer to any gaseous species that can react with thesubstrate surface.

As used herein, the phrase “amorphous hydrogenated carbon,” alsoreferred to as “amorphous carbon” and denoted as a-C:H, refers to acarbon material with no long-range crystalline order which may contain asubstantial hydrogen content, for example on the order of about 10 to 45atomic %. Amorphous carbon is used as a hard mask material insemiconductor applications because of its chemical inertness, opticaltransparency, and good mechanical properties.

Plasma enhanced chemical vapor deposition (PECVD) is widely used todeposit amorphous carbon films due to cost efficiency and film propertyversatility. In a PECVD process, a hydrocarbon source, such as agas-phase hydrocarbon or vapors of a liquid-phase hydrocarbon that havebeen entrained in a carrier gas, is introduced into a PECVD chamber. Aplasma-initiated gas, typically helium, is also introduced into thechamber. Plasma is then initiated in the chamber to create excitedCH-radicals. The excited CH-radicals are chemically bound to the surfaceof a substrate positioned in the chamber, forming the desired amorphouscarbon film thereon. Embodiments described herein in reference to aPECVD process can be carried out using any suitable thin film depositionsystem. Examples of suitable systems include the CENTURA® systems whichmay use a DXZ® processing chamber, PRECISION 5000® systems, PRODUCER®systems, PRODUCER® GTTM systems, PRODUCER® XP Precision™ systems,PRODUCER® SETM systems, Sym3® processing chamber, and Mesa™ processingchamber, all of which are commercially available from Applied Materials,Inc., of Santa Clara, Calif. Other tools capable of performing PECVDprocesses may also be adapted to benefit from the embodiments describedherein. In addition, any system enabling the PECVD processes describedherein can be used to advantage. Any apparatus description describedherein is illustrative and should not be construed or interpreted aslimiting the scope of the implementations described herein.

Device manufacturers using an amorphous carbon hard mask layer demandtwo critical requirements be met: (1) very high selectivity of the hardmask during the dry etching of underlying materials and (2) high opticaltransparency in the visible spectrum for lithographic registrationaccuracy. As used herein, the term “dry etching” generally refers toetching processes where a material is not dissolved by immersion in achemical solution and includes methods such as reactive ion etching,sputter etching, and vapor phase etching.

One of the limitations of currently available amorphous carbon films isthe hydrogen content of the film. The high hydrogen content of the filmscan lead to poor etch selectivity.

Hard masks are used as etch stop layers in semiconductor processing.Ashable hard masks have a chemical composition that allows them to beremoved by a technique referred to as ashing once they have served theirpurpose. An ashable hard mask is generally composed of carbon andhydrogen with trace amounts of one or more dopants (e.g., nitrogen,fluorine, boron, silicon). In a typical application, after etching, thehard mask has served its purpose and is removed from the underlyinglayer. This is generally accomplished, at least in part, by ashing, alsoreferred to as “plasma ashing” or “dry stripping.” Substrates with hardmasks to be ashed, generally partially fabricated semiconductor wafers,are placed into a chamber under vacuum, and oxygen is introduced andsubjected to radio frequency power, which creates oxygen radicals(plasma). The radicals react with the hard mask to oxidize it to water,carbon monoxide, and carbon dioxide. In some instances, complete removalof the hard mask may be accomplished by following the ashing withadditional wet or dry etching processes, for example when the ashablehard mask leaves behind any residue that cannot be removed by ashingalone.

Hard mask layers are often used in narrow and/or deep contact etchapplications, where photoresist may not be thick enough to mask theunderlying layer. This is especially applicable as the criticaldimension shrinks.

FIGS. 1A-1E illustrate schematic cross-sectional views of a substrate100 at different stages of an integrated circuit fabrication sequenceincorporating an amorphous carbon layer as a hard mask, according to thePrior Art. A substrate structure 150 denotes the substrate 100 togetherwith other material layers formed on the substrate 100. FIG. 1A (priorart) illustrates a cross-sectional view of a substrate structure 150having a material layer 102 that has been conventionally formed thereon.The material layer 102 may be a low-k material and/or an oxide, e.g.,SiO₂. FIG. 1B (prior art) depicts an amorphous carbon layer 104deposited on the substrate structure 150 of FIG. 1A. The amorphouscarbon layer 104 is formed on the substrate structure 150 byconventional means, such as via PECVD. The thickness of amorphous carbonlayer 104 is variable, depending on the specific stage of processing.Typically, amorphous carbon layer 104 has a thickness in the range ofabout 500 Å to about 10,000 Å. Depending on the etch chemistry of theenergy sensitive resist material 108 used in the fabrication sequence,an optional capping layer (not shown) may be formed on amorphous carbonlayer 104 prior to the formation of energy sensitive resist material108. The optional capping layer functions as a mask for the amorphouscarbon layer 104 when the pattern is transferred therein and protectsamorphous carbon layer 104 from energy sensitive resist material 108. Asdepicted in FIG. 1B, energy sensitive resist material 108 is formed onamorphous carbon layer 104. The layer of energy sensitive resistmaterial 108 can be spin-coated on the substrate to a thickness withinthe range of about 2000 Å to about 6000 Å. Most energy sensitive resistmaterials are sensitive to ultraviolet (UV) radiation having awavelength less than about 450 nm, and for some applications havingwavelengths of 245 nm or 193 nm. A pattern is introduced into the layerof energy sensitive resist material 108 by exposing energy sensitiveresist material 108 to UV radiation 130 through a patterning device,such as a mask 110, and subsequently developing energy sensitive resistmaterial 108 in an appropriate developer. After energy sensitive resistmaterial 108 has been developed, the desired pattern, consisting ofapertures/openings 140, is present in energy sensitive resist material108, as shown in FIG. 1C (prior art). Thereafter, referring to FIG. 1D(prior art), the pattern defined in energy sensitive resist material 108is transferred through amorphous carbon layer 104 using the energysensitive resist material 108 as a mask. An appropriate chemical etchantis used that selectively etches amorphous carbon layer 104 over theenergy sensitive resist material 108 and the material layer 102,extending apertures 140 to the surface of material layer 102.Appropriate chemical etchants include ozone, oxygen, or ammonia plasmas.Referring to FIG. 1E (prior art), the pattern is then transferredthrough material layer 102 using the amorphous carbon layer 104 as ahard mask. In this process step, an etchant is used that selectivelyremoves material layer 102 over amorphous carbon layer 104, such as adry etch, i.e. a non-reactive plasma etch. After the material layer 102is patterned, the amorphous carbon layer 104 can optionally be strippedfrom the substrate 100.

Current carbon hard mask films are deposited at very high temperaturesand have low hydrogen (H) content, but the films are largely sp²,resulting in lower density and modulus, leading to lower etchselectivity and pattern integrity. Modulus is a measurement of themechanical strength of the film. Films, particularly thick films, withlow modulus have line wiggling and other issues.

In one or more embodiments, a high sp³ amorphous carbon film isadvantageously deposited. In one or more embodiment, the deposition isdone at low temperatures using diamondoid precursors.

In one or more embodiments, to achieve greater etch selectivity, thedensity and, more importantly, the Young's modulus of the carbon film isimproved. One of the main challenges in achieving greater etchselectivity and improved Young's modulus is the high compressive stressof such a film making it unsuitable for applications owing to theresultant high wafer bow. Hence, there is a need for carbon(diamond-like) films with high-density and modulus (e.g., higher sp³content, more diamond-like) with high etch selectivity along with lowstress (e.g., <−500 MPa).

As used herein, the terms “diamond-like” and/or “diamonoid” refer to aclass of chemical compounds having a diamond crystal lattice.Diamondoids may include one or more carbon cages (e.g. adamantine,diamantine, triamantane, and high polymantanes). Diamondoids of theadamantine series are hydrocarbons composed of fused cyclohexane ringswhich form interlocking cage structures. Diamondoids may be substitutedand unsubstituted caged compounds. These chemical compounds may occurnaturally, or can be synthesized. Diamondoids have a high sp³ contentand also have a high C:H ratio. In the general sense, diamond-likecarbon materials are strong, stiff structures having dense 3D networksof covalent bonds.

Embodiments described herein, include improved methods of fabricatingcarbon hard mask films with high-density (e.g., >1.8 g/cc), high Young'selastic modulus (e.g., >150 GPa), and low stress (e.g., <−500 MPa). Inone or more embodiments, the Young's modulus is measured at roomtemperature, or at ambient temperature, or at a temperature in the rangeof from about 22° C. to about 25° C. In one or more embodiment, Young'smodulus of the diamond-like carbon may be greater than 150 GPa,including greater than 160 GPa, greater than 170 GPa, greater than 180GPa, greater than 190 GPa, greater than 200 GPa, greater than 210 GPa,greater than 220 GPa, greater than 230 GPa, greater than 240 GPa, andgreater than 250 GPa. In one or more embodiment, Young's modulus of thediamond-like carbon may be greater than 200 GPa. The carbon filmsfabricated according to the embodiments described herein are amorphousin nature and have a higher etch selectivity with much greater modulus(e.g., >150 GPa) along with lower stress (<−500 MPa) than currentpatterning films. In one or more embodiment, the stress is less than−500 MPa. In one or more embodiment, the stress is about −250 MPa. Inone or more embodiment, the stress is in a range of about −250 MPa toless than about −500 MPa. In one or more embodiment, the stress is lessthan about −250 MPa.

In one or more embodiment, the diamond-like carbon film has a Young'sModulus, measured at room temperature, of greater than 250 GPa and astress of about −250 MPa.

In one or more embodiment, the diamond-like carbon film has a Young'sModulus, measured at room temperature, of greater than 250 GPa and astress of about −250 MPa.

In one or more embodiment, the density of the diamond-like carbon isgreater than 1.8 g/cc, including greater than 1.9 g/cc, and includinggreater than 2.0 g/cc. In one or more embodiment, the density of thediamond-like carbon is about 2.1 g/cc. In one or more embodiment, thedensity of the diamond-like carbon is in a range of about greater than1.8 g/cc to about 2.2 g/cc. In one or more embodiment, the density ofthe diamond-like carbon is greater than about 2.2 g/cc.

The diamond-like carbon films fabricated according to the embodimentsdescribed herein not only have a low stress but also have a high sp³carbon content.

In one or more embodiments, a method comprising a film on a substrate isdescribed. In one or more embodiment, the method comprised forming afilm on a substrate by exposing the substrate to a diamond-like carbonprecursor having an sp³ content greater than 40 percent.

An advantage of the diamond-like carbon film of one or more embodimentsis the enhancement of etch selectivity when compared to other amorphouscarbon films. FIGS. 2A-2E illustrate schematic cross-sectional views ofa substrate 200 at different stages of an integrated circuit fabricationsequence incorporating diamond-like carbon layer as a hard mask. Asubstrate structure 250 denotes the substrate 200 together with othermaterial layers formed on the substrate 200. FIG. 2A illustrates across-sectional view of a substrate 200 having a material layer 202 thathas been conventionally formed thereon. In one or more embodiment,substrate 200 has at least one feature selected from a peak, a trench,or a via. The material layer 202 may be a low-k material and/or anoxide, e.g., SiO₂. FIG. 2B depicts diamond-like carbon film 204deposited on the material layer 202. The diamond-like carbon film 204 isformed on the substrate structure 250 by conventional means. In one ormore embodiment, the diamond-like carbon layer 205 is formed onsubstrate 200 by pulsed plasma enhanced chemical vapor deposition(PECVD). The thickness of diamond-like carbon film 204 is variable,depending on the specific stage of processing. Typically, diamond-likecarbon film 204 has a thickness in the range of about 300 Å to greaterthan or equal (≥) to about 20,000 Å, depending upon whether theapplication is for logic or for memory. Because of the etch chemistry ofthe diamond-like carbon film 204 used in the fabrication sequence, acapping layer does not need to be formed on diamond-like carbon film 204prior to the formation of energy sensitive resist material 208. Asdiscussed above, a capping layer functions as a mask for an amorphouscarbon layer when the pattern is transferred therein and protectsamorphous carbon layer from energy sensitive resist materials. Withoutintending to be bound by theory, it is believed that the higher densityand modulus of the diamond-like carbon film 204 are a result of the highcontent of sp³ hybridized carbon atoms in the film, which result in ahard mask layer that is highly etch selective, eliminating the need fora capping layer.

In an embodiment, the substrate 200 comprises a semiconductor material,e.g., silicon (Si), carbon (C), germanium (Ge), silicon germanium(SiGe), gallium arsenide (GaAs), indium phosphide (InP), indium galliumarsenide (InGaAs), aluminum indium arsenide (InAlAs), othersemiconductor material, or any combination thereof. In an embodiment,substrate 200 is a semiconductor-on-isolator (SOI) substrate including abulk lower substrate, a middle insulation layer, and a topmonocrystalline layer. The top monocrystalline layer may comprise anymaterial listed above, e.g., silicon. In various embodiments, thesubstrate 200 can be, e.g., an organic, a ceramic, a glass, or asemiconductor substrate. Although a few examples of materials from whichthe substrate 200 may be formed are described here, any material thatmay serve as a foundation upon which passive and active electronicdevices (e.g., transistors, memories, capacitors, inductors, resistors,switches, integrated circuits, amplifiers, optoelectronic devices, orany other electronic devices) may be built falls within the spirit andscope of the present disclosure.

In one embodiment, substrate 200 includes one or more metallizationinterconnect layers for integrated circuits. In at least someembodiments, the substrate 300 includes interconnects, for example,vias, configured to connect the metallization layers. In at least someembodiments, the substrate 200 includes electronic devices, e.g.,transistors, memories, capacitors, resistors, optoelectronic devices,switches, and any other active and passive electronic devices that areseparated by an electrically insulating layer, for example, aninterlayer dielectric, a trench insulation layer, or any otherinsulating layer known to one of ordinary skill in the art of theelectronic device manufacturing. In one embodiment, the substrate 200includes one or more layers above substrate 200 to confine latticedislocations and defects.

The diamond-like carbon film 204 may be formed on the substrate 200 byany technique known to those of skill in the art including, but notlimited to, chemical vapor deposition (CVD), thermal chemical vapordeposition (CVD), plasma enhanced chemical vapor deposition (PECVD),etc. The thickness of diamond-like carbon film 204 is variable. In oneor more embodiment, the diamond-like carbon film 204 may have athickness in a range of about 10 nm to about 30 nm. A thickness in therange of about 10 nm to about 30 nm makes the diamond-like carbon film204 particularly suited for logic applications. In one or moreembodiment, the thickness of the diamond-like carbon film 204 is in themicron range, making it particularly suited for memory (DRAWM/NANA)applications.

As depicted in FIG. 2B, energy sensitive resist material 208 is formedon diamond-like carbon film 204. The layer of energy sensitive resistmaterial 208 can be spin-coated on the substrate to a thickness withinthe range of about 2000 Å to about 6000 Å. Most energy sensitive resistmaterials are sensitive to ultraviolet (UV) radiation having awavelength less than about 450 nm, and for some applications havingwavelengths of 245 nm or 193 nm. A pattern is introduced into the layerof energy sensitive resist material 208 by exposing energy sensitiveresist material 208 to UV radiation 230 through a patterning device,such as a mask 210, and subsequently developing energy sensitive resistmaterial 208 in an appropriate developer. After energy sensitive resistmaterial 208 has been developed, the desired pattern, consisting ofapertures/openings 240, is present in energy sensitive resist material208, as shown in FIG. 2C. Thereafter, referring to FIG. 2D, the patterndefined in energy sensitive resist material 208 is transferred throughdiamond-like carbon film 204 using the energy sensitive resist material208 as a mask. An appropriate chemical etchant is used that selectivelyetches diamond-like carbon film 204 over the energy sensitive resistmaterial 208 and the material layer 202, extending apertures 240 to thesurface of material layer 202. In one or more embodiments wherein thediamond-like carbon film 204 is etch selective and strip selective overspin-on-carbon (SOC). Appropriate chemical etchants include ozone,oxygen, or ammonia plasmas. Referring to FIG. 2E, the pattern is thentransferred through material layer 202 using the diamond-like carbonfilm 204 as a hard mask. In this process step, an etchant is used thatselectively removes material layer 202 over diamond-like carbon film204, such as a dry etch, i.e. a non-reactive plasma etch. After thematerial layer 202 is patterned, the diamond-like carbon film 204 canoptionally be stripped from the substrate 200.

In some embodiments, the diamond-like carbon films described herein maybe formed by chemical vapor deposition (plasma enhanced and/or thermal)processes using hydrocarbon-containing gas mixtures including precursorshaving a formula (I) or a formula (II)

wherein each of R₁-R₂₀ are independently selected from H, a halogen or asubstituted or unsubstituted C₁-C₄ alkyl.

As used herein, “halogen” refers to one or more of a group of element inthe periodic table, more particularly fluorine (F), chlorine (Cl),bromine (Br), iodine (I), and astatine (At).

As used herein, “alkyl,” or “alk” includes both straight and branchedchain hydrocarbons, containing 1 to 20 carbons, in the normal chain,such as methyl, ethyl, propyl, isopropyl, butyl, t-butyl, isobutyl,pentyl, hexyl, isohexyl, heptyl, 4,4-dimethylpentyl, octyl,2,2,4-trimethyl-pentyl, nonyl, decyl, undecyl, dodecyl, the variousbranched chain isomers thereof, and the like. Such groups may optionallyinclude up to 1 to 4 substituents. In one or more embodiments, each ofR₁-R₁₀ are independently from H, a halogen, or a substituted orunsubstituted C₁-C₄ alkyl.

In one or more embodiment, the diamond-like precursor comprises one ormore of adamantane, bromo-adamantane, chloro-adamantane,fluoro-adamantane, iodo-adamantane, di-bromoadamantane,di-chloroadamantane, di-fluoroadamantane, di-iodoadamante, iceane,diamantane, triamantane, isotetramantane, pentamantane,cyclohexamantange, divinyladamantane, 1,2-dimethyladamantane,1,3-dimethyladamantane, bicyclo[2.2.1]hepta-2,5-diene(2,5-norbornadiene), adamantine (C₁₀H₁₆), or norbornene (C₇H₁₀).

The deposition process may be carried out at temperatures ranging from−50 degrees Celsius to 600 degrees Celsius. The deposition process maybe carried out at pressures ranging from 0.1 mTorr to 10 Torr in aprocessing volume. The hydrocarbon-containing gas mixture may furtherinclude any one of, or a combination of any of He, Ar, Xe, N₂, H₂. Thehydrocarbon-containing gas mixture may further include etchant gasessuch as Cl₂, CF₄, NF₃ to improve film quality. The plasma (e.g.,capacitive-coupled plasma) may be formed from either top and bottomelectrodes or side electrodes. The electrodes may be formed from asingle powered electrode, dual powered electrodes, or more electrodeswith multiple frequencies such as, but not limited to, 350 KHz, 2 MHz,13.56 MHz, 27 MHz, 40 MHz, 60 MHz and 100 MHz, being used alternativelyor simultaneously in a CVD system with any or all of the reactant gaseslisted herein to deposit a thin film of diamond-like carbon for use as amandrel. The high etch selectivity of the diamond-like carbon film isachieved by having higher density and modulus than current generationfilms. Not to be bound by theory but it is believed that the higherdensity and modulus are a result of the high content of sp³ hybridizedcarbon atoms in the film, which in turn may be achieved by a combinationof low pressure and plasma power.

In some embodiments, hydrogen radical are fed through an RPS, whichleads to selective etching of sp² hybridized carbon atoms therebyincreasing the sp³ hybridized carbon atom fraction of the film further,thus further increasing the etch selectivity.

The quantity/percentage of sp³ hybridized carbon atoms in the asdeposited diamond-like carbon may vary from application to application.In various embodiments of the present disclosure, the as-depositeddiamond-like carbon film may contain at least 40, 45, 50, 55, 60, 65,70, 75, 80, or 85 percent of sp³ hybridized carbon atoms. Theas-deposited diamond-like carbon film may contain up to 45, 50, 55, 60,65, 70, 75, 80, 85, or 90 percent of sp³ hybridized carbon atoms. Theas-deposited diamond-like carbon film may contain from about 50 to about90 percent of sp³ hybridized carbon atoms. The as-deposited diamond-likecarbon film may contain from about 60 to about 70 percent of sp³hybridized carbon atoms.

In one or more embodiments, the high-density diamond-like carbon filmwith high sp³ content, which is used as a hard mask, shows good etchselectivity versus oxide/nitride and also excellent strip selectivityversus existing hard masks and spin-on-carbon (SOC).

In one or more embodiment, the diamond-like carbon precursors may becombined with one or more additional precursor selected from C₂H₂, C₃H₆,CH₄, or C₄H₈.

Another advantage of the method of one or more embodiments is that alower temperature process may be used to produce a diamond-like carbonwith the desired density and transparency. Ordinarily, higher substratetemperature during deposition is the process parameter used to encouragethe formation of a higher density film. When the diamond-like carbonprecursors of one or more embodiments are used, substrate temperaturemay be reduced during deposition, for example to as low as about lessthan 0° C. and less than about 10° C., about room temperature, or about22° C. to about 26° C., and still produce a film of the desired density,i.e., greater than about 1.8 g/cc, including greater than about 1.9g/cc, and including greater than about 2.0 g/cc. Hence, the method ofone or more embodiment may produce a relatively high density film withan absorption coefficient as low as about 0.04. Further, lowerprocessing temperatures are generally desirable for all substrates,since this lowers the thermal budget of the process, protecting devicesformed thereon from dopant migration. Additionally, lower processingtemperatures are generally desirable for emerging memory applications.

In one or more embodiments, the diamond-like carbon film is depositedwith the use of a plasma. In other embodiment, the diamond-like carbonfilm is deposited without the use, in the absence of, a plasma.

In one or more embodiment, the diamond-like carbon precursor is heatedin an ampoule and is flowed to the substrate with a carrier gas. As usedherein, the term “carrier gas” refers to a fluid (either gas or liquid)that can move a precursor molecule from one location to another. Forexample, a carrier gas can be a liquid that moves molecules from a solidprecursor in an ampoule to an aerosolizer. In some embodiments, acarrier gas is an inert gas. In one or more embodiment, a carrier gas isone or more of hydrogen (H₂), argon (Ar), helium (He), xenon (Xe),nitrogen (N₂), or krypton (Kr).

In one or more embodiment, the diamond-like carbon film is a hard masklayer.

In one or more embodiment, the substrate has a layer to be patterned.

In one or more embodiment, the substrate comprises one or more of anadhesion layer or a dielectric layer.

One or more embodiments provide a method of etching a substrate. As usedherein, the term “etching” refers to a process to chemical remove layersfrom the surface of a substrate, e.g. wafer, during semiconductormanufacturing. Etching is a critically important process duringsemiconductor manufacturing, and every substrate undergoes many etchingsteps before it is complete. In one or more embodiment, the substrate isprotected from the etchant by a masking material, which resists etching.In one or more embodiments, the hard mask material is a photoresist,which has been patterned using photolithography.

In one or more embodiments, the diamond-like carbon is a hard mask,which has been patterned using photolithography or other methods knownto those of skill in the art. In one or more embodiments, thediamond-like carbon may make patterning more difficult due to thedensity of the film.

One or more embodiments provide a method of etching a substrate.Referring to FIG. 3A, in one or more embodiment, a diamond-like carbonhard mask 304 is formed on a substrate 300. In one or more embodiment,the diamond-like carbon hard mask has at least one opening 340 and isformed by exposing the substrate to a diamond-like carbon precursorhaving a structure of formula (I) or a structure of formula (II)

wherein each of R₁-R₂₀ are independently selected from H, a halogen, ora substituted or unsubstituted C₁-C₄ alkyl. In one or more embodiment,the substrate 300 is etched through the at least one opening 340.

In one or more embodiment, the diamond-like carbon hard mask is formedat a temperature less than about 100° C. and a pressure in the range ofabout 1 mTorr to about 100 Torr. In one or more embodiments, thediamond-like carbon hard mask 304 has been patterned usingphotolithography or other methods known to those of skill in the art.

In one or more embodiments, a photoresist 302 is formed on the substrate300 prior to etching. In one or more embodiments, the photoresist 302 isformed between the substrate 300 and the diamond-like carbon hard mask304. Referring to FIG. 3B, in one or more embodiment, the photoresist306 is formed on the diamond-like carbon hard mask 304.

Referring to FIG. 3C, after the substrate 300 is etched, in one or moreembodiments, the diamond-like carbon hard mask 304 is removed. In one ormore embodiment, the diamond-like carbon hard mask 304 is removed byashing.

In the foregoing specification, embodiments of the disclosure have beendescribed with reference to specific exemplary embodiments thereof. Itwill be evident that various modifications may be made thereto withoutdeparting from the broader spirit and scope of the embodiments of thedisclosure as set forth in the following claims. The specification anddrawings are, accordingly, to be regarded in an illustrative senserather than a restrictive sense.

What is claimed is:
 1. An electronic device comprising a film on asubstrate, wherein the film comprises a diamond-like carbon materialhaving a structure of formula (II)

wherein each of R₁₃-R₂₀ are independently selected from H, a halogen, ora substituted or unsubstituted C₁-C₄ alkyl, and wherein the film has aYoung's modulus greater than 180 GPa, measured at room temperature. 2.The electronic device of claim 1, wherein the diamond-like carbonmaterial comprises one or more of bicyclo[2.2.1]hepta-2,5-diene(2,5-norbornadiene) or norbornene (C₇H₁₀).
 3. The electronic device ofclaim 1, wherein the film has a density greater than 1.8 g/cc.
 4. Theelectronic device of claim 1, wherein the film is etch selective andstrip selective over spin-on-carbon (SOC).
 5. The electronic device ofclaim 1, wherein the film is a hard mask layer.
 6. The electronic deviceof claim 1, wherein the substrate comprises at least one featureselected from a peak, a trench, or a via.
 7. The electronic device ofclaim 1, wherein the film further comprises C₂H₂, C₃H₆, CH₄, or C₄H₈.